NOx reduction and Urea Solution For Marine Engines

Global delivery of NOxCare 40 (AUS 40) urea solution

Ships are required to reduce their nitrogen oxide emissions in certain waters. These areas are called Emission Control Areas (ECA) or NOx Emission Control Areas (NECA). The proven technology to reduce NOx emissions from marine engines is SCR (selective catalytic reduction). SCR using a urea solution as the reducing agent is consider to be a key technology for reducing NOx emission. SCR can reduce NOx emissions from ships by 99%.

In order to operate, a ship’s SCR system requires a high purity urea solution. The systems are sensitive to potential chemical impurities in the urea solution. Even small amounts of contaminant can severely impact the performance of the SCR system and can ruin the catalyst elements. The quality of the urea solution needs to be specified to ensure reliable and stable operation of the SCR system. The ISO 18611 series provide the specification of urea solution for quality, handling, transportation and storage.

Marine urea reagent is non-toxic, safe to handle, transport and store, making it practical for use in maritime vessels equipped with SCR systems.

NOxCare 40 for NOx control: 

  • Meets the ISO standard implemented for Urea Solution for Marine SCR applications 
  • Is produced by Yara, one of the world’s largest urea producer, thus securing product supply
  • Is available worldwide
  • Is non-toxic, safe and easy to transport, store and handle
  • Has unmatched levels of quality to ensure longevity of the SCR catalyst 
  • Verifies product batches according to the highest industry standards
  • Has strict quality control procedures throughout its logistics chain 

Why use NOxCare 40% urea solution for NOx reduction in marine vessels? 

We do not recommend the use of AUS32.5%, which is currently used in automotive vehicles, in maritime applications. 32,5 % urea solution has a freezing point at -11 °C whilst 40% urea solution has a freezing point at 0°C. Onboard vessels, the urea solution tank is normally located below the sea surface level. Consequently, contrary to vehicles’ urea product, it will rarely or never be exposed to temperatures below 0 °C and this allows for a higher concentration of urea in the solution.

This yields better economy for the vessels because one carries less water and more urea.

It is more economical
It ensures longevity of the SCR catalyst
  • Fewer refuellings needed 
  • Lower logistics (delivery) costs 
  • The need to store and carry less water content results in lower operational costs
There is a greater percentage of high purity urea - the active compound needed for chemical conversion in the SCR system

How is NOxCare 40 (AUS40) made available to refill ships with SCR systems?

Ferries and Cruise ships
Supply vessels or other coastal vessels
Tankers, cargo and other deep sea vessels
Fixed departure times and points, can be supplied by full truckloads or containers directly from our production sites or local storage tanks Refill at offshore bases or bunker stations Refill when they leave/arrive at port. This can either be done by full truckloads or containers directly from production sites or local storage tanks

Where port entry is unauthorized or the ship is too large, we can arrange trans-shipment using barges, supply vessels or tankers to your vessel.

Can I get NOxCare 40 (AUS40) if I am outside a NECA? 

Yes, it will also be available in areas outside the (N)ECAs, either by local production or overseas deliveries in ISO containers, flexitank containers or IBCs (Intermediate Bulk Containers). 

All the steps in the NOxCare 40 supply chain are secured according to the quality requirement for AUS40.

Parameter Unit Specification
Urea concentration
Alkalinity as NH3
Phosphorus (as PO4)
% by weight
% by weight
% by weight
max 0,8
max 0,5
max 100
max 50
max 1
max 1
max 1
max 1
max 1